Transcription

• It is the process of formation of DNA to RNA.
• The types of RNA include:

a) mRNA: Contain and carry genetic information coded in DNA to the cytoplasm and finally attached to ribosome.

b) rRNA: Role in protein synthesis.

c) tRNA: Carry amino acids to the site of protein synthesis.

Process of transcription

a) Initiation:

• It involves binding of RNA polymerase to promoter region of DNA.

b) Elongation:

• Once the promoter region has been recognized by the holoenzyme, it results to local unwinding of DNA helix.
• After binding, RNA polymerase begins to synthesize DNA sequence and sigma subunit is released.

c) Termination:

• The elongation of RNA chain continues until a termination signal is reached.
• The RNA polymerase stops synthesis and the nascent RNA is separated from the DNA template.